One tool for every weight unit
A bag of flour in grams, a package for shipping in pounds, a person's weight in stone. Weights are listed in whatever unit the local custom prefers, and you often need another.
The converter covers milligrams, grams, kilograms, metric tons, ounces, pounds and stones. Type a value, pick the units and the answer shows up with the exact formula used.
The basics
A kilogram is 1,000 grams. A gram is 1,000 milligrams. A metric ton, also written tonne, is 1,000 kilograms. The metric side is neat because it's all powers of ten.
The imperial side is not. A pound is 16 ounces. A stone is 14 pounds, used mostly in the UK and Ireland for body weight. The bridge between systems is the pound: 1 pound is exactly 0.45359237 kilograms.
- 1 kg = 2.2046 pounds
- 1 pound = 453.6 grams
- 1 ounce = 28.35 grams
- 1 stone = 6.35 kilograms
Pounds to kilograms in your head
Divide by 2.2. For 150 pounds, that's about 68 kilograms. A quicker guess: halve it and take off 10 percent of the half. 150 halves to 75, minus 7.5, gives 67.5. Close enough for most uses.
Going the other way, double the kilos and add 10 percent. 70 kg doubled is 140, plus 14 is 154 pounds. The true figure is 154.3.
Where it matters
Shipping costs jump at weight breaks, and carriers measure in pounds or kilograms depending on the country. Cooking from an overseas recipe often needs grams. Gym plates come in pounds or kilos, and mixing them up leads to an awkward lift.
Medication doses use milligrams, and a slip there is serious. Always double-check a dose with a pharmacist, not a converter.
Tonnes and tons
These get confused. A metric tonne is 1,000 kg, about 2,205 pounds. A US short ton is 2,000 pounds. A UK long ton is 2,240 pounds. The three are close but not equal, and for freight the difference adds up.
Your inputs never leave your browser.
Mistakes that cost money
Weight conversions look trivial until a shipment is wrong. A parcel quoted in pounds and billed in kilograms can change the price band. A recipe that mixes ounces by weight with fluid ounces by volume comes out wrong every time. They're different units that happen to share a name.
Check which ounce you mean. Troy ounces, used for gold and silver, weigh about 31.1 grams. The everyday avoirdupois ounce is about 28.35 grams. Mix them up on a bullion purchase and the gap is real money.
The stone is still common in the UK for body weight. One stone is 14 pounds, or about 6.35 kilograms. If a friend says they weigh 11 stone 4, that's 158 pounds, near 71.7 kilograms.
Rounding rules that work
Convert first, round last. If you round at each step, small errors stack up. For cooking, the nearest gram is plenty. For shipping, round up, since carriers do. For lab work, keep the digits your scale actually reports and no more.
A scale that reads to the nearest 100 grams doesn't earn you the right to quote 72.346 kilograms. Match your output to the precision of the input.
Bookmark the pairs you use often. Most people only need two or three, like pounds and kilograms, or ounces and grams.
Quick reference
These are rounded, good enough for planning.
- 1 kilogram is about 2.205 pounds
- 1 pound is 453.6 grams
- 1 ounce is about 28.35 grams
- 1 stone is 14 pounds
- 1 metric tonne is 1,000 kilograms
Everyday conversions
A newborn weighing 3.4 kilograms is about 7 pounds 8 ounces. A 20 kilogram airline bag is 44 pounds. A 150 gram steak is a little over 5 ounces. These come up at hospitals, airports and butchers, and a fast converter takes the guesswork out.
For gym plates, a 20 kilogram bar set is 44.1 pounds, though many gyms label the 45 pound plates as roughly 20.4 kilograms. Strength logs mix both systems, so pick one and stick to it.
For postage, always weigh the packed parcel, not the item. Packing adds more than you expect.